Even in modern times we are fascinated by crystals - from the diamonds we use as a sacred symbol of partnership, to the plethora of 'healing' gems that can be found in a New Age gift shop. So we can only imagine how ancient people viewed these transparent rocks with hidden structure.

Evidence of the esteem in which crystals were held can be found in a "remarkable set" of 'crystal weapons' found in the megalithic tombs of southwestern Spain. At the site of Valencina de la Concepcion, archaeologists have uncovered crystal arrowheads, an exquisite dagger blade, and cores used for creating the artifacts, that date to the 3rd millennium BCE.

The Montelirio tholos, excavated between 2007 and 2010, is "a great megalithic construction...which extends over 43.75 m in total", constructed out of large slabs of slate. At least 25 individuals were interred within the structure , along with "an extraordinary set of sumptuous grave goods...the most notable of which is an unspecified number of shrouds or clothes made of tens of thousands of perforated beads and decorated with amber beads". Additionally however, a large number of crystal arrowheads were found together, which be suggestive of a ritual offering at an altar. The arrowheads have the characteristic long lateral appendices of flint arrowheads from the area - but investigators remarked that "even greater skill must have been required to produce these unique features when using rock crystal."

The manufacture of the rock crystal dagger blade must have been based on an accumulation of transmitted empirical knowledge and skill taken from the production of flint dagger blades as well from know-how of rock-crystal smaller foliaceous bifacial objects, such as Ontiveros and Montelirio arrowheads... It was obtained from a large monocrystal at least 220 mm in length and 60 mm in width. Given that these single crystals are hexagonal, they would have a similar width along all their different axes. The rock crystal source used in creating the crystal weaponry has not been pinpointed exactly at this stage, though analysis suggests two potential sources, "both located several hundred km away from Valencina".

Danish scientists have invented a revolutionary crystalline material that can absorb and store oxygen in high concentrations. A bucket of such material can suck the oxygen out of a room, which could potentially wave goodbye to heavy oxygen masks.

Imagine if you could get rid of the bulky scuba tank while taking a dive. Now, imagine practically any task to which the storage and timely release of oxygen is absolutely essential. And you have the new crystal developed at the University of Southern Denmark, with help from the University of Sydney, Australia.

A few microscopic grains are enough for one gulp of air, but a bucketful - or 10 liters - can completely suck the oxygen out of a room. "In the lab, we saw how this material took up oxygen from the air around us," Professor Christine McKenzie, who led the study, said.

When different things are exposed to oxygen, they react differently - from wine to food to living organisms, varying factors (pressure, temperature etc.) and time of exposure can fundamentally alter things. However, what you get with the new discovery is a way of controlling oxygen by not reacting with it. This was ascertained by using x-ray diffraction, showing the material's atomic behavior when it was full of oxygen, then when it was depleted of it.

"An important aspect of this new material is that it does not react irreversibly with oxygen - even though it absorbs oxygen in a so-called selective chemisorptive process. The material is both a sensor, and a container for oxygen - we can use it to bind, store and transport oxygen - like a solid artificial hemoglobin," McKenzie says. "It is also interesting that the material can absorb and release oxygen many times without losing the ability. It is like dipping a sponge in water, squeezing the water out of it and repeating the process over and over again," she continues.

To release the stored oxygen, all that is needed is to heat up the material, or pressure it. And those are just the known, natural ways. McKenzie and the team are now looking further than that.

We thought it was necessary to put together the Crystals parts into a movie like we did with the human history chapter. We've been pretty busy with our road trip and haven't had much time to work on Spirit Science, but there are a lot of things going on and its all beautiful! Enjoy!